Many of current electronic apparatuses utilize a fan to generate air cooling together with a filter to prevent excessive air dust or particles entering into the apparatus. Examples are LCD projectors, computer servers or even computers, air fresher, intensive light bulbs, to name a few. For these apparatus, one of the major failure modes is the overheating when the filter clogs and fails to allow air circulation. Prior approach is to use a temperature sensor to monitor the raise of the temperature inside the apparatus but often temperature sensor can only provide local temperature sensing and the response lags far behind the malfunction of cooling fan. Furthermore, a clogged filter may not be always quick enough to result in a rapid temperature elevation, particularly in a relatively cold area. Hence, the situation of a clogged filter may not be correctly and properly detected by a temperature sensor. Fujiwara et al. (U.S. Pat. No. 7,062,963; Omron: MEMS flow sensors) teaches a device that can be used for this purpose. However, the device has a limited flow dynamic detection due to its complicated flow passages design. The curved wall surface and bypass configuration will cause the particles in air flow to block the bypass channel and add additional failure mode to its installed devices. Therefore, it is very desirable to design a new air flow path clog sensor to meet the current needs in industry.